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GLUT-3 (brain-type) glucose transporter polypeptides in human blood platelets
J D Craik1, M Stewart, C I Cheeseman
1Chemistry Department, Bishop's University, Lennoxville, Quebec, Canada.
Thrombosis Research
|September 15, 1995
Summary
Human platelets express the GLUT-3 glucose transporter, identified using specific antibodies and radiolabeling. This transporter facilitates glucose uptake, distinguishing it from GLUT-1 and GLUT-2 isoforms.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Glucose transporters are crucial for cellular energy metabolism.
- Different glucose transporter isoforms (GLUTs) exhibit tissue-specific expression.
- Human platelets are anucleated cells involved in hemostasis and thrombosis, requiring glucose for energy.
Purpose of the Study:
- To identify the specific glucose transporter isoform(s) present in human platelets.
- To confirm the functional presence of glucose transporters in platelets.
Main Methods:
- Immunoblotting using antiserum against human GLUT-3.
- Photoaffinity labeling with 3H-cytochalasin B.
- Competition assays with D-glucose and L-glucose.
Main Results:
- Immunoblots detected polypeptides of 46-48 kDa, consistent with GLUT-3, in human platelets.
- Photoaffinity labeling identified similar molecular weight polypeptides, indicating glucose transporter binding.
- Labeling was inhibited by D-glucose but not L-glucose, confirming glucose transporter specificity.
- Minimal GLUT-1 and no GLUT-2 transporters were detected.
Conclusions:
- Human platelets primarily express the GLUT-3 glucose transporter isoform.
- Platelet glucose uptake is mediated by GLUT-3, distinct from GLUT-1 and GLUT-2.
- This finding has implications for understanding platelet energy metabolism and function.